code: def train_dataloader(self):
      return DataLoader(self.mnist_train, batch_size=self.batch_size)
  
imports: from os import path
  from typing import Optional
  import torch
  from lightning.pytorch import LightningDataModule, LightningModule, cli_lightning_logo
  from lightning.pytorch.cli import LightningCLI
  from lightning.pytorch.demos.mnist_datamodule import MNIST
  from lightning.pytorch.utilities.imports import _TORCHVISION_AVAILABLE
  from torch.nn import functional
  from torch.utils.data import DataLoader, random_split
label_desc: Use image node_id 2 for calling the MyDataModule obj's underlying member method code with example usage: obj.train_dataloader() and returns: DataLoader